ToC path:

mco_iot_replicator_sync

Start the node's synchronization.

For an overview see page ARF Applications in C

Prototype

 
    MCO_RET mco_iot_replicator_sync(mco_iot_replicator_h repl, 
                        mco_iot_agent_id_t agent_id, 
                        int flags);

Arguments

repl The replicator object

agent_id

The device_id to synchronize or one of the following constants:

`MCO_IOT_ALL_AGENTS`	Synchronize all connected devices
`MCO_IOT_SERVER_AGENT_ID`	Denotes the server node
`MCO_IOT_ALL_UP_AGENTS`	All directly or indirectly connected nodes with a lower level value
`MCO_IOT_ALL_DOWN_AGENTS`	All directly or indirectly connected nodes with a higher level value

flags

The bitmask value of a combination of the following synchronization flags:

MCO_IOT_SYNC_PUSH	Send (push out) modification to a node (or to all nodes). The server sends all modified data from downtable classes, while the device sends all modified data from its uptable classes
MCO_IOT_SYNC_PULL	Request modifications from remote nodes
MCO_IOT_SYNC_NONBLOCK	Ensure that the socket is not blocking (a memory buffer is used when the socket is blocked to temporarily cache transmission requests)
MCO_IOT_SYNC_WAIT	Wait until the requested operations complete. If the request is to push (`MCO_IOT_SYNC_PUSH`) then wait until `ACK` is received from the remote node; if the request is to pull (`MCO_IOT_SYNC_PULL`) then wait until all data is received
MCO_IOT_SYNC_BOTH	Equivalent to `MCO_IOT_SYNC_PUSH \| MCO_IOT_SYNC_PULL`
MCO_IOT_SYNC_DEEP_ACK	If set, the data must be acknowledged by the destination node. This ensures that the destination has received the data but can delay receiving ACK if the destination is busy or not available. If this flag not set, the data acknowledged by the directly connected node (router). Later, the router will deliver data to the destination.
MCO_IOT_SYNC_RESEND	Usually mco_iot_replicator_sync() doesn't re-send data that was already sent but not ACKed. This flag forces to resend all non-ACKed data. This can be useful if the position of the node in the ioT network was changed.
MCO_IOT_SYNC_CHILDS	If set, the data is delivered to the destination node and all its direct and indirect children.

Description

The function starts the node's synchronization. Note that:

a ) If the MCO_IOT_SYNC_WAIT flag is not set, the function returns immediately after the data is written to the socket. The subsequent events, receiving ack for the push and data for the pull, must be handled in the callbacks

b) The flags MCO_IOT_SYNC_NONBLOCK and MCO_IOT_SYNC_WAIT are incompatible

c) The flag MCO_IOT_SYNC_WAIT is not allowable when the agent_id is MCO_IOT_ALL_AGENTS (it can’t synchronously wait for all agents to respond)

Return Codes

MCO_S_OK	Synchronization successfully started
MCO_S_IOT_NO_NEW_DATA	No new data were inserted or updated since the previous call of `mco_iot_replicator_sync()`. Note that this is not error but status code
MCO_E_IOT_INVALID_HANDLE	Invalid replicator handle `repl`
MCO_E_ILLEGAL_PARAM	Incompatible parameter values (e.g. neither `PULL` nor `PUSH` specified; `NONBLOCK` and `WAIT` specified together etc.)
MCO_E_IOT_WRONG_AGENT_ID	The `agent_id` is not valid
MCO_E_IOT_AGENT_NOT_FOUND	The device or server with the specified `agent_id` was not found
MCO_E_NOMEM	Unable to allocate memory for internal structures
MCO_E_WRITE_STREAM	Unable to write the replicated data to the socket
MCO_E_SESLIMIT	Or other `connect()` errors if the function can't create a database connection
`mco_trans_start()` errors	Error starting a transaction
`mco_trans_commit()` errors	Error committing a transaction
other errors	Other errors can happen when accessing database to serialize changes

Example

The code snippet below initializes the ARF (IoT) runtime, opens and connects the database, creates the communicator and replicator objects, then connects and synchronizes the replicator:

     
    int main(int argc, char *argv[])
    {
        mco_db_params_t db_params;
        mco_device_t dev;
        mco_db_h db;
        mco_iot_replicator_params_t repl_params;
        mco_iot_comm_params_t comm_params;
        mco_iot_replicator_h repl;
        mco_iot_comm_h comm;
        const char *conn_string = (argc > 1) ? argv[1] : "127.0.0.1:15000";
        ...
 
        /* Initialize eXtremeDB and IoT runtimes */
        mco_error_set_handler(&sample_errhandler);
        mco_runtime_start();
        mco_iot_init();
 
        /* Create database */
        dev.type       = MCO_MEMORY_CONV;
        dev.assignment = MCO_MEMORY_ASSIGN_DATABASE;
        dev.size       = DEVICE_DATABASE_SIZE;
        dev.dev.conv.ptr = (void*)malloc(dev.size);
        mco_db_params_init (&db_params);
        db_params.db_max_connections = 5;
 
        if (argc > 2) {
            db_params.iot_agent_id = atoi(argv[2]); /* Override the agent_id in the schema */
        }
        CHECK(mco_db_open_dev(db_name, iotdevice_get_dictionary(), &dev, 1, &db_params));
        CHECK(mco_db_connect(db_name, &db));
        mco_iot_comm_params_init(&comm_params);
        CHECK(mco_iot_comm_create(&comm_params, &comm));
        mco_iot_replicator_params_init(&repl_params);
        CHECK(mco_iot_replicator_create(db, comm, &repl_params, &repl));
        ...
        CHECK(mco_iot_replicator_connect(repl, conn_string, 2*1000, 0));
        ...
        CHECK(mco_iot_replicator_sync(repl, MCO_IOT_SERVER_AGENT_ID, MCO_IOT_SYNC_PULL | MCO_IOT_SYNC_PUSH | MCO_IOT_SYNC_WAIT));
    }

Files

Header file:

mcoiot.h

Source file:

mcoiotrepl.c

Library:

libmcoiotrepl.a